Your historical attention span is too short. Read the title search. The land of the current state of Israel and the West Bank were Jewish land 3000 years ago. It was Jewish land when the Romans arrived in 63 BC. Jews lived there when the Arabs conquered Jerusalem in 637 CE/AD.
There's never been a Palestinian state there, not in 637, not when the Mamelukes ruled it, not when the Ottomans ruled it from 1517-1918. Never.
And the PLO leader Zahir Mohsen said in 1977 that Palestinians are no different from Egyptians, Jordanians, Syrians, Lebanese and that Palestinian nationality was just a tactical invention.